For Patients & Caregivers
Bottom Line: Ellagic acid is found in many foods that are part of a healthy diet, but there is no evidence to support its use for cancer treatment.
Ellagic acid is a naturally occurring compound called a tannin. It can be isolated from foods such as red raspberries, strawberries, and walnuts, and has been studied in the laboratory, but not in humans. In laboratory animals, ellagic acid showed cancer-preventive properties. For example, rats fed ellagic acid before and during exposure to carcinogens (cancer-causing substances) developed fewer liver tumors than rats fed a normal diet. Similar results were shown in mice with lung or esophageal cancer. Scientists think that ellagic acid exerts these effects in two ways. First, ellagic acid enhances the activity of certain detoxification enzymes in the liver, speeding up the removal of dangerous substances from the body, while it also inhibits the cytochrome P450 liver enzymes and may prevent them from metabolizing carcinogens into more dangerous forms. Second, ellagic acid causes changes in the cell cycle of cancer cells in the test tube, leading to cell death. However, neither of these promising effects have been shown to occur in the human body.
- To prevent cancer
Although experiments in the laboratory and in animals suggest that ellagic acid may have anti-cancer properties, these results are not always transferable to the human body. No studies have been performed in humans to test whether ellagic acid is safe and effective.
- To lower cholesterol
One study found that consumption of a drink made with freeze-dried strawberry powder for 4 weeks lowered total cholesterol and LDL levels in obese women with metabolic syndrome. However, further research is needed to confirm this effect.
Sixteen women with at least three features of metabolic syndrome (waist circumference > 35 inches, triglycerides > 150 mg/dl, fasting blood glucose between 100 mg/dl and 126 mg/dl, HDL < 50 mg/dl or blood pressure > 130/85 mm/Hg) were enrolled. Participants consumed one cup of strawberry drink (25 g freeze-dried strawberry powder in water) twice daily for four weeks. Study results showed that short-term supplementation with freeze-dried strawberries appears to have a hypocholesterolemic effect and decrease lipid peroxidation in women with metabolic syndrome.
For Healthcare Professionals
A phenolic compound derived from ellagitannins commonly found in red raspberries, strawberries and walnuts, ellagic acid has antiviral and antibacterial properties (1)(2). A small clinical study found that ellagic acid may lower cholesterol and decrease lipid peroxidation in patients with metabolic syndrome (7). Other studies have reported that ellagic acid is a potent antioxidant (1)(8).
Pre-clinical studies indicate anticarcinogenic effects of ellagic acid against liver, esophageal, prostate, and colorectal cancer cell lines (3)(4)(5)(6). It was also shown to induce apoptosis and potentiate all-trans retinoic acid myeloid differentiation therapy in human leukemia HL-60 cells (9). However, human studies have yet to be conducted.
In another study, pomegranate-derived ellagitannins exhibited anti-aromatase activity and suppressed testosterone-induced breast cancer cell proliferation, but ellagic acid did not have such effects (10).
Ellagic acid appears to inhibit chemical-induced esophageal carcinogenesis in animals (11). It down-regulates insulin-like growth factor IGF-II (6) and activates p53/p21 expression, leading to cell cycle arrest at the G1/S phase and apoptosis (12). In vitro studies report that ellagic acid protects cells from oxidative DNA damage caused by hydrogen peroxide and bleomycin (8). Ellagic acid’s ability to induce detoxification enzymes NADPH and quinone reductase contribute to some of its chemopreventive activities (13). Conversely, certain cytochrome P450 enzymes are inhibited by ellagic acid, preventing other carcinogens from being metabolized into more mutagenic forms (14)(15).
Ellagitannins from berries and nuts are hydrolyzed in the intestine into ellagic acid. Animal models show that some of the ellagic acid is further metabolized by microflora in the intestine. After absorption, ellagic acid and its metabolites are localized preferentially in the lung tissues and, to a lesser extent, in the liver tissues (16). Metabolites are excreted and detected in urine and feces (17).
Basu A, et al. Freeze-dried strawberry powder improves lipid profile and lipid peroxidation in women with metabolic syndrome: baseline and post intervention effects. Nutr Journal. 2009 Sept;8:43.
This study investigated the effect of freeze-dried strawberry powder on plasma lipid levels and biomarkers of oxidative stress and inflammation in women with metabolic syndrome. Sixteen women with at least 3 features of metabolic syndrome (waist circumference > 35 inches, triglycerides > 150 mg/dl, fasting blood glucose between 100 mg/dl and 126 mg/dl, HDL < 50 mg/dl or blood pressure > 130/85 mm/Hg) were enrolled. Subjects consumed one cup of strawberry drink (25 g freeze-dried strawberry powder in water) twice daily for four weeks. Fasting blood analyses, anthropometrics, dietary intake, blood pressure, biomarkers of oxidative stress and inflammation, and plasma ellagic acid levels were all evaluated at baseline and again at four weeks. Study results indicated that mean serum total cholesterol and LDL-cholesterol levels were significantly lower at 4 weeks compared to baseline (-5% and -6%, respectively [p<0.05]). Lipid peroxidation, as indicated by malondialdehyde and hydroxynonenal, was also reduced (-14%, p < 0.01). Markers of inflammation, such as C-reactive protein and adiponectin, were not affected. Increased plasma ellagic acid levels were detected in 81% of subjects at four weeks without any change in dietary intake compared to baseline.
The authors concluded that short-term supplementation with freeze-dried strawberries appears to have a hypocholesterolemic effect and decrease lipid peroxidation in women with metabolic syndrome.